First and foremost, you have potential. Remember that as you read this, because I don't want to make you give up on your writing. Rather, I want to give you the feedback that I hope will help you.

I honestly think that this story was MUCH too OOC. In the novel, Matt is an abusive, controlling jerk, and as the antagonist of the story, he is not portrayed as sympathetic whatsoever. In your fanfic, he is a misunderstood soul who has redeemed himself. What I want to know is how he got to that point. Also, it's implied that, while the official story is that Josie hated herself for loving Matt, she was actually in love with the idea of being with him and popularity. In this, she's totally in love with him.

Also, putting in Anna seemed random. You mention her family, but it feels out of place.

Overall, not bad. Your prose is nice, and you can spell, which is more than I can say for a lot of writers.